Preparation of organoaluminum compounds in the presence of a catalytic amount of ti, zr, nb, v, sc, u, or hf



United States Patent PREPARATION OF ()RGANOALUMlNUM CiBM- POUNDS DI THE PRESENCE DE A CATALYTHI AMQUNT 0F Ti, Zr, Nb, V, Sc, U, 0R HE Frederick J. Radd and Warren W. Woods, Ponca City, Okla, assignors to Continental Gil Company, Ponca City, 0kla., a corporation of Delaware No Drawing. Filed Sept. 26, 1960, Ser. No. 58,222

24 Claims. (Cl. 260-448) The present invention relates, in general, to an im proved process for preparing organoaluminum con pounds. More particularly, the invention relates to the use of catalytic elements which provide improved reaction rates in the preparation of organoaluminum compounds. In a preferred embodiment, the invention relates to aluminum alloys containing catalytic elements, Which aluminum alloys provide improved reaction rates in the preparation of dialkylaluminum hydrides. In another em- 7 72 2 2 5 3 3A1 a s 2 Belgian Patent No. 546,432, issued March 24, 1956, to

Karl Ziegler gives a description of this method. While this method has many advantages, it. does have the dis advantage of having a relatively slow reaction rate.

The diethylaluminum hydride formed in the process of this invention can be reacted with ethylene 'to produce triethylaluminum as follows:

The over-all efifectcf the two reactions, then, is to produce three moles of triethylaluminurn for each two moles of triethylalmninurn initially present. 7 The triethylaluminum gained from these processes can then be subjected to a growth reaction with additional olefin and the .growth product in turn is converted into high-molecularweight alcohols and a-oleiins. These latter processes are well known to those skilled in the art.

While the preceding discussion has been concerned with diethylaluminum hydride and triethylaluminum, it may be well to note, again, that this has been solely for purposes of illustration. The present invention is not limited thereto. This will be apparent from a later discussion and the examples.

It is also known to prepare organoaluminum compounds (e.g., triethylaluminum) by the direct reaction of aluminum metal with hydrogen and an olefin. Such a process is disclosed by Horace E. Redman in US. Patent No. 2,787,626, issued April 2, 1957. Specifically, this patentee teaches a process for preparing triethylalurninum which comprises contacting comminuted aluminum (e.g., as aluminum shavings prepared under nitrogen) with sufficient triethylaluminum to Wet the metal surface and then heating the reaction zone to a temperature between about 30 and 130 C. under 10 to 300 atmospheres pressure of a gaseous mixture containing hydrogen and ethylene. It is an object of the present invention to provide aluminum ,alloys which containa reaction-promoting amount of one or more added catalytic' metals.

3*,1'84252 Patented Septl'], 1963 It is still another object of the present invention to provide a process for preparing organoaluminumcompounds wherein improved reaction rates are obtained in the process by using a reaction-promoting amount of one or more added catalytic metals.

It is yet another object of the present invention to provide a means for overcoming the harmful effects of certain elements when present in aluminum, and when said aluminum is used in the preparation of orga'noaluminum compounds, said means comprising the use of an aim minum alloy containing, in addition to the harmful elements, a reaction-promoting, and intentionally added, amount of one or more catalytic elements.

it is a preferred object of the present invention to provide an improved process for preparing dialkylaluminum 'hydrides wherein improved reaction rates are obtained in the process by the use of a reaction-promoting amount of one or more added catalytic metals.

It is another preferred object of the present invention to provide an improved process for preparing dial' kylaluminum hydride, wherein improved reaction rates are obtained in the process by the use of an aluminum alloy containing a reaction-promoting, and intentially added, amount of one or more catalytic metals.

Broadly stated, the present invention resides in our discovery that the use of a reaction-promoting amount of one or more catalytic elements in conjunction with aluminum gives improved reaction rates in processes wherein aluminum is used in the production of organoaluminum compounds. We have discovered, also, that, in such processes, the use of aluminum alloys containing a reaction-promoting amount of one or more catalytic elements is more'effective than the use of aluminum and the catalytic elements separately (i.e., not in alloyed form). We have also discovered that some elements do not increase the reactivity of aluminum when said aluminum (in alloy form) is used in the production of organoaluminum compounds. In addition, we have also discovered that some elements decrease the efficacy of the catalytic elements in the aluminum. By inference, then, we believe that these elements show a retarding or negative effect on the aluminum. We have discovered that by increasing the amount of the catalytic elements, the effect of these negative elements can be overcome.

Before proceeding to specific examples which illustrate our invention, it may be well to describe in general the materials of our invention and the terms used herein.

The term organoaluminum compounds as used herein refer to compounds having the general formula wherein R is a hydrocarbon radical, and R and R are hydrogen, halogen, or a hydrocarbon radical. The aforementioned hydrocarbon radical can contain from 2 to 40 carbon atoms andcan be alkyl, aryl, alkaryl, or aralkyl.

Our invention is suitable for preparing organoaluminum compounds, such as the following:

Diethylaluminum chloride Diethylaluminum bromide Diisobutylaluminum chloride Diisobutylaluminum bromide Dioctylaluminum chloride Dipentadecylaluminum bromide Didocosylaluminurn chloride Diphen-ylaluminum hydride Diphenylaluminum chloride 3 Di-para-tertiarybutylphenyl aluminum hydride Di-para-tertiarybutylphenyl aluminum chloride Diphenyloctylalumium hydride Diphenyloctylaluminum chloride Triphenylaluminum Tri-para-tertiarybutylphenyl aluminum Triphenyloctylaluminum Our invention is particularly suitable for preparing organoaluminum compounds, such as the following:

Diethylaluminum hydride Diisobutylaluminum hydride Dioctylaluminum hydride Dipentadecylaluminum hydride Didocosylaluminum hydride Ditetracontylaluminum hydride Triethylaluminum Triisobutylaluminum Trioctylaluminum Tripentadecylaluminum Tridocosylaluminum The elements which we have found to improve the eflicacy of aluminum, in processes wherein aluminum is used to produce organoaluminum compounds, are the following: titanium, zirconium, niobium, vanadium, hafnium, scandium, and uranium. It is of interest that in general these elements conform to the following designation: (1) they are hydride formers; (2) most of the elements (at least titanium, zirconium, vanadium, and niobium) form peritectic binary systems with aluminum, and (3) they are apparently electronegative to aluminum even though :scandium, uranium, and hafnium appear to be above aluminum in the usual chart. While most of the elements which work are peritectic-forrners with aluminum, all of the elements which form peritectics with aluminum do not work. For example, barium, lanthanum, and cerium will form a peritectic with aluminum. Yet, they do not work in our invention. It should be noted that, while we have tested some fifty-one metallic elements in aluminum alloys, only the above-listed seven have been found to work.

Of the elements which work in our invention, the following are preferred: titanium, zirconium, niobium, vanadium, scandium, and uranium. Still further, of these, titanium and zirconium are the most preferred. In addition, it should be noted that combinations of the elements can be used.

We have found that the efficacy of the elements varies. For example, for a given level of reactivity in 99.99 percent aluminum, we have found that 200 parts per million (p.p.m.) of titanium is equalled, roughly, by 20 p.p.m. zirconium. In order to more concisely teach our invention, the following tables give the lower limits of eflicacy for the catalytic elements of our invention.

Table I gives the lower limits of efiicacy for the catalytic elements when incorporated in very pure (99.99 percent) aluminum. Table 11 gives the lower limits of efficacy for the catalytic elements when incorporated in aluminum of about 99.4 percent purity, which corressponds to commercially available aluminum.

TABLE I Lower Effective Limits of Catalytic Elements in 99.99 Percent Aluminum 4 TABLE 11 Lower Efiective Limits 0 Catalytic Elements in 99.4 Percent Aluminum In the preceding tables the term suitable refers to that lower limit which shows a perceptible optical or weight loss effect on the reaction involved. The term preferred refers to that lower limit wherein a practically important effect is noted.

While theoretically no upper limit exists for these catalytic elements, we believe that, from a practical viewpoint, it is not necessary, under most circumstances, to add more than 2 percent (by weight) of the catalytic element or elements to the aluminum. Uusually, it will not be necessary to add more than 1 percent (by weight) of the catalytic element or elements to the aluminum.

In addition, it may be well to mention that each increase in the amount of catalytic element in the aluminum alloy to a certain level gives an improvement in reactivity. Stated another way, the higher the concentration of the catalytic element in the aluminum alloy, the greater the reactivity. However, for each element, there is a point of diminishing benefits or leveling off. In other words, at this point the addition of more catalytic elements produces only a slight increase in reactivity. We believe that in plant practice it is desirable to use levels of catalytic elements at least equal to or greater than the preferred levels, but the plant levels will, for purposes or economy, be less than the 2 percent indicated as the muimum. For example, in plant practice it is desirable, when using titanium or zirconium, to use these elements in an amount of at least 0.02 percent, preferably 0.05 percent, by weight.

Wehave found that certain elements (e.g., iron, silicon, copper, tin, lead, and nickel) adversely affect the reactivity of the aluminum. The first three of this series occur as natural impurities in most commercially available aluminums. These elements are referred to as negative elements in the sense that they act to decrease the elfectiveness of the catalytic elements. However, we have found that the increased addition of the catalytic elements overcomes the effect of the negative elements. Since some of these negative elements (e.g., iron and silicon) are found in some of the commercial grades of aluminum, our invention has considerable commercial significance. It is readily apparent that the addition of one or more of our catalytic elements can convert an inactive aluminum (i.e., an aluminum which is unreactive or very slow in processes for preparing organoaluminum compounds) to an active aluminum.

In addition, we have found that combinations of the catalytic elements can be used. In other words, the ternary and quaternary aluminum alloys containing the catalytic elements can be used.

The term aluminum alloy as used herein and in the appended claims refers to aluminum alloys wherein the catalytic elements have been deliberately added to the aluminum. The catalytic elements can be added to the aluminum by any of the means known to those skilled in the art. Examples of metallurgical means by which the catalytic elements can be added include the following (1) the elements can be added directly; (2) the elements, alloys, or inorganic salts can be added to the primary electrolysis cells; and (3) reductive compounds or mixtures of the elements can be added to the melting furnace.

In addition, the term aluminum alloy as used herein and in the appended claims refers to aluminum alloys containing at least 98 percent by weight of aluminum.

Another means by which the catalytic elements can be used is by blending aluminum alloys containing a higher than-necessary concentration of the catalytic elements with aluminum or aluminum alloys containing none, or less than a reaction-promoting amount, of the catalytic elements. By this means, reaction-promoting amounts of the catalytic elements can be maintained in the reaction system.

[While we do not wish to be bound by any particular theoretical hypothesis as to how these alloying metals accelerate the reaction, our present belief is that the effect is catalytic and positive in nature. The term catalytic elements has been used herein in order to have a generic term for the elements which work effectively for reaction acceleration in the aluminum alloys used in preparing organoalurninum compounds. From the evidence we have obtained, it appears that the observed catalytic effect is not due to reduction in grain size, which coincidentally occurs in most of the catalytic aluminum alloys used.

It may be well to explain that when we refer herein to improvements in the reaction rate, in processes for preparing organoaluminum compounds, we mean for the term to include associated decreases in induction time. It is readily apparent that both serve to decrease the overall reaction time, which is the primary practical concern.

The shape or form of the aluminum alloy used in preparing organoaluminum compounds does not fall within the scope of our invention. Generally, workers in this field have used comminuted aluminum (e.g., atomized particles or machined shavings) because a large surface area per unit of weight is afforded. In addition, it is often customary to treat the aluminum to remove any coating of aluminum oxide. Ball milling of aluminum powder in a kerosene-triethylaluminum solution is an example of the latter procedure. Regardless of the form ditions were maintained for 1 hour.

consumed- EXAMPLE III The procedure of Example II was followed with the exception that 28 grams (1.04 moles) of the pure aluminum rod of Example I was used. Approximately 26 grams of unreacted aluminum was recovered at the end of the procedure. The yield of diethylaluminum hydride was 7 percent of theoretical based on the aluminum conum EXAMPLE 1v in order to more rapidly evaluate the efficacy of various aluminum alloys, a screening test was used. The equipment consisted of a standard, one liter, stirred (640 rpm.) autoclave. A stainless steel sample holder was mounted upon the stirrer shaft so as to hold eight cylindrical test specimens of %-inch diameter by l-in. length. In conducting a run, one end of each of these cylinders was metallographically polished to afford a sensitive means to study the surface topography after the triethylaluminum-hydrogen solution attacks. The polished cylinders were placed on the sample holder, 500 milliliters of triethylaluminum was added to the autoclave, and the autoclave was pressured with hydrogen or previous treatment of the aluminum, the addition of the catalytic elements improves the reactivity of the aluminum.

The term reaction-promoting amount as used herein term is synonymous with catalytic amount; however, in view of the term catalytic element, the alternative term has been used.

Generally, the reaction of the trialkylaluminum and hydrogen with the aluminum alloy is conducted at a temperature of 80 to 200 C., more preferably 100 to 150, C., and at a pressure of 60 to 350 atmospheres. An excess of hydrogen is used. The reaction will occur at any mole ratio of aluminum to trialkylaluminum of from 0.1 to 1, to 10 to 1.. More preferably, the mole ratio of aluminum to triethylaluminum is from 1 to 1, to 4 to 1.

' The aluminum alloys of our invention can also be used in the process of Redman (U.S. Patent No. 2,787,626),

discussed previously herein. Use of our aluminum alloys containing one or more catalytic elements provides for an increased reaction rate in said process.

In order to disclose more clearly the nature of the present invention and the advantages thereof, reference will hereinafter be made to certain specific embodiments which illustrate the flexibility of the herein-described process. It should be clearly understood, however, that this is done solely byway of example 'and is not to be construed as a limitation upon the spirit and scope of the appended claims. EXAMPLE I lAluminum having a purity of 9999+ percent was used in this example One batchof this aluminum was cast into /s-inch diameter rods. A second batch containing 99.85 percent of the same high-purity aluminum and 0.15 percent of pure titanium metal was cast into %-inch diameter rods. EXAMPLE H I Thirty grams (1.1 moles) of the aluminum rod containing 0.15 percent titanium'of Example I was cut into to 2000 p.s.i.g. and 250 F. The run was conducted for three hours. A standard coupon of alloy of 1000 ppm, titanium in 99.99 percent aluminum was used as a reference in each run. Each coupon was weighed before and after the run.

The alloys tested were prepared by air melting in a pure graphite crucible heated by an electric resistance furnace. A Weighed amount of the alloying element was added to a weighed amount of aluminum of 99.99 percent purity. r

A loss in weight of the coupon indicated that the particular alloy in the coupon was reactive.

Several runs were made using 99.99 percent allu-minum coupons. Due to the limited surface area of the alumi num coupons, due to the fact that these were not mechanicalily or chemically activated, and due to the p-articular reaction conditions, no weight loss was noted for these coupons. 7

'Using this procedure, many aluminum alloys were screened. The results for the ones which showed a weight loss, thereby indicating a catalytic element present, are shown in Table III.

TABLE III AZLUTZUZLHPZ Alloy Reactlvzty; 99.99 Percent Aluminum C0nmmzng Amount Weight;

Element Added, Loss p.p.m. (Gram) 20 0. 0002 0. 0004 800 0. 0036 7, 000 0.0306 20 00006 400 0. 0235 1,000 0. 0464 5,000 0. 0009 s, 000 0.0017 10, 000 0.0061 10,000 0.0006 800 0.0042 1,700 0. 0070 3,700 0.0162 5, 000 0.0304 500 0.0178 Do 5, 000 0. 1026 Uranium 1, 300 0. 0242 EXAMPLE V Using the procedure described in Example IV, tests were run on coupons of 99.4 percent aluminum containing varying amounts of titanium and zirconium. The results of these tests were shown in Table IV.

TABLE IV Aluminum Alloy Reactivity; 99.4 Percent Aluminum Cntuining- Amount, Weight Element p.p.m Loss (Gram) Titanium 1, 100 0. 0055 D 3, 600 0. 0410 5, 200 0. 0408 800 0.0080 3, 400 0.0200 7,000 0. 0375 EXAMPLE V1 Using the procedure described in Example 1V, tests were run on aluminum alloys containing various combinations of catalytic elements. The results of these tests are shown in Table V.

TABLE V Aluminum Alloy Reactivity Alloy 99.99% Al Containing- 1,000 ppm. Titanium (Std) 0.0558 500 ppm. Titanium/500 p.p.m. Hamium 0.0339 500 p.p.m. Zirconium/500 p.p.m. Hainium 0. 0453 600 ppm. Zirconium/500 p.p.m. Titanium 0. 0562 EXAMPLE VII Using the procedure described in Example IV, tests were run on aluminum alloys containing titanium and elements which had previously been shown to be nega- EXAMPLE VIII Using the procedure described in Example IV, tests were runon aluminum alloys containing zirconium and elements which previously had been shown to be negative. The results of these tests are shown in Table VII.

TABLE VII Efiects of Negative Elements on Aluminum-Zirconium Alloys Alloy Weight loss 99.99% Al containing 7 1,0 p.p.m. Zirconium (Std) 0.0567 1,000 p.p.m. Zirconium/3,000 p.p.m. Copper. 0.0131 1,000 p.p.n1. Zirconium/3,000 ppm. Iron. 0. 0414 1,000 p.p.m. Zirconium/3,000 ppm. Silicon 0. 0122 1,000 ppm. Zirconium/3,000 p.p.m. Manganese 0.0332

EXAMPLE IX Charge:

grams triisobutylaluminum 27.3 grams aluminum powder (99.99% pure) Procedure: The triisobutylalu-minum and aluminum powder (which were in a molar ratio of 3 to 4) were charged to a 1-liter, stirred autoclave. The autoclave was heated to 250 and pressured to 2,000 p.s.i.g. with hydrogen. Reaction was conducted for 1 hour. The reaction was then stopped and the products were centrifuged to remove suspended aluminum.

Results: An aluminum analysis of the product indicated that none of the triisobutylaluminum had been converted to diisobutylaluminum hydride.

EXAMPLE X Charge:

150 grams triisobutylaluminum 27.3 grams aluminum alloy powder (99.99% aluminum containing 2,000 ppm. Zirconium) Procedure: The procedure was exactly the same as used in Example IX.

Results: An aluminum analysis of the product indicated that 35.2 percent of the triisobutylaluminum was converted to diisobutylaluminum hydride.

EXAMPLE XI Charge:

150 grams trioetylaluminum 14.8 grams aluminum powder (99.99% pure) Procedure: The procedure was the same as in Ex ample IX.

Results: An aluminum analysis of the product indicated that 3.1 percent of the trioctylaluminum had been converted to dioctylalumin-um hydride.

EXAMPLE XII Charge 15 0 grams trioctylaluminum 14.8 grams aluminum alloy powder (99.99% aluminum containing 2,000 ppm. zirconium) Procedure: The procedure was the same as in Ex ample IX.

Results: An aluminum analysis of the product indicated that 18.8 percent of the trioctylaluminum had been converted to dioctylaluminum hydride.

EXAMPLE XIII Charge 150 grams growth product 1 (sample No. RGR-3-178) 12 grams aluminum powder (99.99% pure) Procedure: The procedure was the same as in Example IX. Results: An aluminum analysis of the product indicated that 9.2 percent of the growth product had been converted to the tdialkylaluminum hydride.

The term growth product refers to a mixture of alkylalum num compound made by repeated addition of ethylene to trialkylaluminum. A typical sample of growth product has the following analysis (alkyl groups).

Carbon content of alkyl group:

Wt. pergent C 59 Cl. 3.52 Co 10.57 Ce 17.17 20.33 18.30 C 13.44 8.27 4.40 2.06 0.85 0.32 0.10 0.04 0.01

EXAMPLE XIV Charge:

150 grams growth product (same as used in Example XII) 12 grams aluminum alloy powder (99.99% aluminum containing 2,000 ppm. zirconium) Procedure: The procedure was exactly the same as used in Example IX.

Results: An aluminum analysis of the product indicated that 27.2 percent of the growth product had been converted to the dialkylaluminnm hydride.

EXAMPLE XV V In this example, three samples of aluminum powder were atomized by the Aluminum Company of America. Two of the samples were prepared from 99.99 percent pure aluminum. The third sample was prepared from 99.99 percent purity molten aluminum ,to which had been added 0.078 percent of titanium.

Each of the samples was ball milled for six hours in a kerosene-triethylaluminum solution. A certain amount, 108 grams or 4 moles, of the-ball-milled aluminum was then changed to a 1-liter autoclave with 342 grams (3 moles) of triethylalunrinum. The autoclave was heated to 120 C. and then pressured to 2,000 psi-g. with hydrogen. These conditions were maintained, depending upon the reactivity of the sample, from 30 minutes to as long as four hours. 77

The results of these tests are shown in Table VIII. 'Ilhe data therein show the percentages of triethylaluminum converted to diethylaluminum hydride for /2 hour, 2 hours, and 4 hours. In addition, the chemical analysis of each powder is shown in Table VIII.

TABLE VIII Reactivity Measurements; Aluminum Powders With and Without Catalytic Elements 1 Impurities probably picked up from atomization equipment.

TABLE IX Reactivity Measurements; Aluminum. Powders With and Without Catalytic Elements Time required Per- Per- Perto obtain Sample No. cent; cent cent Run No. 80%

Ti Fe Si converslon i Al(R)a t0 Al(R) H,

' hours Reynolds LS828- 0.053 0.27 LNV893145.- 0.59 Reynolds LS-8l5- 0.088 0.25 LNV893l34. 0. 29 Reynolds LS-842 0.163 LNV893150. 0.16 Reynolds 120 #6755 0.014 0. 35 0.18 LNV-893-1l8-- 1.54 Reynolds 120 #6994 0.010 0.26 0.14 LNV-8931l7.- 1.59 Reynolds 120 #7000 L 0. 006 0.27 0. 17 LNV-893l03.- 1. 44 Reynolds 120 #7105 0. 004 0.23 LNV893104.- 1.19

Reynolds 120 #7150 0.010 0. 22 LNV-893l23.- 1.16

1 Commercial powder; no titanium added.

EXAlliPLE XVI -In this example, three samples of aluminum powder containing varying amounts of titanium were prepared under commercial aluminum powder production (spray- 10 ing liquid aluminum) conditions by Reynolds Metals Company. The aluminum powder corresponded to Reynolds 120 commercial powder, with the exception of the added titanium. For purposes of comparison, five samples of Reynolds 120 commercial (993+ percent purity) aluminum powders were tested for reactivity. These powders had no titanium added; whatever titanium present occurred naturally. The powder contained small amounts of iron and silicon.

'Ihese eight samples of aluminum powder were ballmilled and were tested for reactivity in the manner de scribed in Example XIV. The results are shown in Table IX. The data therein show the time in hours required to obtain an percent conversion of triethylaluminum to diethylaluminum hydride. U

From the data in Tables VI and VII the activity decreases of the catalytic elements, due to the presence of impurity or negative elements, can be estimated. Using 1000 p.p.m. concentration of titanium and zirconium in the aluminum alloy as the reference point, the results are as shown below.

Ti 1,000 Zr 1,000

Element and Concentration p.p.m., p.p.m.,

percent percent Fe (1 p.p.m.) O. 023 O. 009

(decrease) S1 (1 ppm.) O. 032 0. 026 Cu (1 p.p.m.) -0. 026 O. 026 Mn (1 p.p.m.) O. 022 -0. 014

. pounds, said compounds being characterized as having the general formula wherein R and R are hydrocarbon radicals containing from 2' to 40 carbon atoms and R is selected from the group consisting of hydrogen and a hydrocarbon radical containing from 2 to 40 carbon'atoms, by the reaction of at least an organic compound and aluminum, the im provement comprising carrying out the process in the presence of an added reaction-promoting amount of at least about 5 parts per million of at least one catalytic element selected from the group consisting of titanium, zirconium, niobium, vanadium, scandium, uranium, and hafnium.

2. In a process for preparing organoaluminum compounds, said compounds being characterized as having the general formula wherein R and R are hydrocarbon radicals containing from 2 to 40 carbon atoms and R is selected from the group consisting of hydrogen and a hydrocarbon radical containing from 2 to 40' carbon atoms, by the reaction of at least an organic compound and aluminum, the im provement comprising carrying out the process with an aluminum alloy containing at least 98 weight percent of aluminum and a reaction-promoting amount, at least about 5 parts per million, of at least one added catalytic element selected from the group consisting of titanium,

1.1 zirconium, niobium, vanadium, scandium, uranium, and hafnium.

3. In a process for preparing dialkylaluminum hydride by the reaction of a trialkylaluminum, the alkyl radicals of said trialkylaluminum containing from 2 to 40 carbon atoms, with hydrogen and aluminum at an elevated temperature and superatmospheric pressure, the improvement comprising carrying out the reaction with an aluminum alloy containing at least 98 weight percent aluminum and a reaction-promoting amount, at least about 5 parts per million, of at least one added catalytic element selected from the group consisting of titanium, zirconium, niobium, vanadium, scandium, uranium, and hafnium.

4. The process for the preparation of diethylaluminum hydride comprising reacting triethylaluminum with hydrogen and an aluminum alloy at an elevated temperature and superatmospheric pressure, wherein said aluminum alloy comprises about 98 to about 99.98 percent by weight of aluminum and a reaction-promoting amount in the range of about 0.02 to about 2 percent by weight of at least one added catalytic element selected from the group consisting of titanium, zirconium, niobium, vanadium, scandium, uranium, and hafnium.

5. The process, as defined in claim 2, catalytic element is titanium.

6. The process, as defined catalytic element is zirconium.

7. The process, as defined catalytic element is niobium.

8. The process, as defined catalytic element is vanadium.

9. The process, as defined catalytic element is scandium.

10. The process, as defined in claim 2, catalytic element is uranium.

11. The process, as defined in claim 2, catalytic element is hafnium.

12. A process for the preparation of diethylaluminum hydride comprising reacting triethylaluminum with hydrogen and an aluminum alloy at an elevated temperature and superatmospheric pressure, wherein said aluminum alloy comprises about 99 to about 99.95 percent by weight of aluminum and a reaction-promoting amount in the range of about .05 to about 1 percent by weight of at least one added catalytic element selected from the group consisting of titanium, zirconium, niobium, vanadium, scandium, uranium, and hafnium.

13. The process, as defined in catalytic element is titanium.

14. The process, as defined in catalytic element is zirconium.

15. The process, as defined in catalytic element is niobium.

16. The process, as defined in catalytic element is vanadium.

17. The process, as defined in catalytic element is scandium.

18. The process, as defined in catalytic element is uranium.

19. The process, as defined in catalytic element is hafnium.

20. In a process for preparing trialkylaluminum, the

wherein the in claim 2, wherein the in claim 2, wherein the in claim 2, wherein the in claim 2, wherein the wherein the wherein the claim 12, wherein the claim 12, wherein the claim 12, wherein the claim 12, wherein the claim 12, wherein the claim 12, wherein the claim 12, wherein the alkyl radical of said trialkylaluminum containing from 2 to 40 carbon atoms, by the reaction of aluminum with hydrogen and an olefin at an elevated temperature and superatmospheric pressure, the improvement comprising carrying out the reaction with an aluminum alloy containing at least 98 weight percent aluminum and a reaction-promoting amount in the range of at least about 5 parts per million of at least one added catalytic element selected from the group consisting of titanium, zirconium, niobium, vanadium, scandium, uranium, and hafnium.

21. In a process for preparing triethylaluminum by the reaction of aluminum with hydrogen and ethylene at an elevated temperature and superatmospheric pressure, the improvement comprising carrying out the reaction with an aluminum alloy wherein said aluminum alloy comprises about 98.0 to about 99.98 percent by weight of aluminum and a reaction-promoting amount in the range of about 0.02 to about 2.0 percent by weight of at least one added catalytic element selected from the group consisting of titanium, zirconium, niobium, vanadium, scandium, uranium, and hafnium.

22. In a process for preparing triethylaluminum by the reaction of aluminum with hydrogen and ethylene at an elevated temperature and superatmospheric pressure, the improvement comprising carrying out the reaction with an aluminum alloy wherein said aluminum alloy comprises about 99.0 to about 99.95 percent by weight of aluminum and a reaction-promoting amount in the range of about 0.05 to about 1.0 percent by weight of at least one added catalytic element selected from the group consisting of titanium, zirconium, niobium, vanadium, scandium, uranium, and hafnium.

23. In a process for preparing dialkylaluminum hydride, the alkyl radicals of said dialkylaluminum hydride containing from 2 to 40 carbon atoms, by the reaction of a trialkylaluminum with hydrogen and aluminum at an elevated temperature and superatmospheric pressure, the improvement comprising carrying out the process in the presence of a reaction-promoting amount of at least about 5' parts per million of at least one added catalytic element selected from the group consisting of titanium, zirconium, niobium, vanadium, scandium, uranium, and hafnium.

24. In a process for preparing diethylaluminum hydride by the reaction of triethylaluminum with hydrogen and aluminum at an elevated temperature and superatmospheric pressure, the improvement comprising carrying out the process in the presence of a reaction-promoting amount of at least about 5 parts per million of at least one added catalytic element selected from the group consisting of titanium, zirconium, niobium, vanadium, scandium, uranium, and hafnium.

References Cited in the file of this patent UNITED STATES PATENTS 2,787,626 Redman Apr. 2, 1957 2,900,402 Johnson Aug. 18, 1959 2,922,714 Benham Jan. 26, 1960 2,931,722 Urban Apr. 5, 1960 2,971,969 Lobo Feb. 14, 1961 FOREIGN PATENTS 215,426 Austria June 12, 1961 

1. IN A PROCESS FOR PREPARING ORGANOALUMINUUM COMPOUNDS, SAID COMPOUNDS BEING CHARACTERIZED AS HAVING THE GENERAL FORMULA 